"attacking in a way that maximizes their chances of hurting you and leaves them the least vunerable to counter attack" doesn't describe what aiki is, to me. Striking arts rarely evidence any aiki - it's not terribly useful for strikes, though it will happen at times. It's not exactly rare in any grappling art, though many don't actually work with it much, so they are less likely to make full use of it. Aiki is an approach to getting them moving with very little effort. It's more about finding the place where there's no resistance (or, better yet, where they are actually giving the force/momentum/energy needed to throw them, so you don't have to).
I'm not saying that one can't use competition training for self-defense. I'm saying it doesn't work for developing aiki, because once someone knows what they are dealing with, they can remove most opportunities for aiki. It's a limitation inherent in training aiki. This is one of my problems with the schools that focus on aiki, without building alternatives, and claim to be helping develop self-defense skills. Aikido works for self-defense, but not if it's limited to only the purely aiki movements (except, perhaps, for those with extreme skill levels). Strikes, leverage (Jujutsu/Judo style throws and locks), etc. round out the possibilities.
I think a reasonable comparison would be a haymaker sucker punch. It can work, even on a trained person, when standing in a bar. It's unlikely to be effective in the middle of a boxing or MMA round, because it's not going to be a surprise. Unless you've set them up for it with a lot of other work, that haymaker isn't going to connect. In a surprise situation, though, it's a much higher percentage move.
That's a quirk of aiki. It's actually easier to execute the core principles (not the exact techniques, the principles that make them work) when someone comes "full noise", as you put it. Someone punching to take a head off gives the kind of weight commitment that makes an Aikido throw feel easy to the thrower.
Again, kind of my point. Pure aiki training is not a good solution for self-defense, IMO. Now, that trained opponent will usually give what Aikido needs when he's angry. You can see that when high-level MMA competitors get out of control at photo ops and stuff. Those guys would never give that kind of weight commitment to an opponent in the cage, but when they are shoving, they often over-commit their weight.
Grappling doesn't actually create as many opportunities for aiki, unless the person does something stupid like pull away as hard as they can. It will create openings for leverage throws and the like. Look at what happens in Judo competitions. They eventually manage a throw, but rarely is it because their opponent over-committed their weight somewhere. If I grapple with someone trained, they'll likely drop/control their weight (far less chance of aiki). If I grapple with someone untrained, they'll likely get more tense and muscle things (again, less chance of aiki). I need them moving for aiki, and strikes do a better job of that.
